Pre-65 Bikes

I've just acquired a Bantam trialler, with a view to replacing the SY250 heap of engineering sh*te that I got the other week. The new steed is a 1969 D14/4, I understand, a bit heavier, like me, but at least the plug can be changed without removing the tank and radiator, and the float bowl removed without the prior removal of tank, rear mudguard, air filter/box, muffler, aluminium spreader plate, and gas shock. The frogs must be taking the pus. Back to the plot - I don't know what petroil mix to feed the Rooster on. I was using Morris' "Sport Action 2" synthetic oil in the sulking frog, but that is a lot different to the "Gloopy" stuff that we used to have 40 years a…

Hi could any body out ther tell me if Serco is still going, as I have tried the phone number everyday for the last 2 weeks and do the still supply aluminum barrels, big ends and gears.

Just a thought, how does Sam's original Ariel compare to modern versions? Have the machines moved on so much that even GOV132 would now struggle.

Hi, Would like to know what modifiations should be made to a D14. 4 speed motor to make it competitive and reliable in Pre 65 trials ? Expecting to use alloy barrell, modified Fantic head ?, electronic ignition, replacement carb, etc, etc. Would be great to hear from someone who has done this recently and built a good engine ? Thanks, Jon.

Hello all wonder if you can help. I have just got round to getting my Dad's old B40 out after been sat for 15 years. It doesn't seem to have any spark and I've been told they have electronic ignition is that true? So I'm a bit stumped.

Does anyone know if there is a splined kickstart shaft available for the early distributor type C15 (Star?) engine? It's a 1963 engine. Really fed up having to drift out cotterpins every time I have to remove the kickstart. No matter which type I use they bend and really take some hammering to remove. The knuckle on my forefinger really hurting and being twice it's normal size thanks to the hammer was the last straw this tonight... Or I may have to investigate the possiblility of grafting a splined shaft from something else onto the C15 gear - or rather I will have to talk nicely and grovel to someone else... That sort of stuff is beyond my capabilities

Further to my post regarding the Cub oil return mod, I have now started stripping the engine to find a cause for the smoking. The engine was built from bits and pieces and put in my spare frame for my Son to ride. It starts and runs ok. He entered its first trial and almost completed the first lap with no issues. It then started smoking badly on tickover so we retired the bike. I carried out a number of the usual mods when I built it including adding a blind camshaft bush and putting a large breather in the unused distributor hole, Alpha big end, etc etc. I also fitted a new (later type) oil pump. I measured the clutch and gearbox oil when I removed it …

Having recently fitted a new 22mm Amal concentric carb to my cub, to try to cure low rev stalling in sections I am still having problems curing a flat spot which happens if i snap open the throttle from idle. i called Surrey Cycles for advice they suggested fitting a brass slide with a bigger cutaway which i fitted today. i took the Cub for a run on road to warm it up and then tried to trickle along at idle occasionally bliping the trottle to lighten the front flat spot is still there - again only if the throttle is snapped open, if the throttle is opened slower it revs cleanly all the way through the range. Do you think this may be an ignition problem, I am using a Boye…

what is the ultimate pre65 bike? bsa etc

I have recently fitted new UPB PVL type electronic ignition and UPB Delorto Carb to my cub in an attempt to make it run better. I consider these good pieces of kit and already set up to run with my engine. (Bob is very helpful). The engine currently oils plugs and appears to run rich. It dies when the throttle is opened quickly and will not rev above 1/2 throttle. The symptoms get a bit better each time a new plug is fitted but not great. I didn't rebore the barrel when I built it as it seemed o.k. I fitted a good standard piston with new rings (all at +40"). This is my 1st engine build. It seemed to run o.k once the rings bedded in but has got proressivly worse…

Help guys, what would you do with a genuine 'Comerfords cub', my dilemma is do I restore it back to former glory or do I go all modern using all the trick bits now available.I am fully aware that it is not competitive in its original trim but would it still be desirable as I don't think there are that many around any more.At the end of the day they are only a converted 'Mountain Cub' but as rough as they are they are still part of 'Triumphs' famous trialing history.

OK took the B40 for it's first run today up at Burrycliffe. Didnt enter as this was the first time the bike has actually moved under it's own power, well if you dont count 20 yds down the drive, and as of 10:00 last night i had just finished the airfilter. So had a little ride around before the trial, observed a section to help out, then had a little ride after. Actually i was quite surprised as it wasnt that bad all things considered, oil leak from the front fork seals also the rocker spindles and chain case but nothing some silicone wont cure. The chain did jump off once however and after talking to a couple of guys with Faber framed B40's they said the chain tens…

I know Serco is the place for Cub engine work but who's the guru on frame/fork mods. And who supplies parts and info for trials Triumph unit twins and BSA C15s/B40s?.

I have a distributor BSA C15 engine I intend to build for trials, I have a WD low ratio box, I want to keep it 250cc, also intend to keep the bush bearing having a new phosphor bronze one made to suit. Having removed the top end all looks good so far, not run for a while but sound. PVL or Electrex ignition will be used. Has anyone any more tips for a soft 250cc build?? Thanks in advance...

Help needed, I need a valve lifter assembly for a 1961 B40, bolts to rocker cover. Can anyone help with this. B**ger to start without one !!

Any recommendations for the best soldering iron to make up cables? I've been struggling with a gas torch which is just simply to hot. Also any hints on the best solder to use?

For my sins, I have just bought a 1962 C15 (distributor model) which looks the part of a trials bike but has a standard road version engine. It has a 375 monobloc Amal carb. I am going to change the engine duplex sprocket for a 18T and the gearbox sprocket for a 13T with a 64T on the rear wheel. Once I have taken off the lights, got it to run smoothly at low revs and got used to Pirelli tyres I hope to trial it. Am I on the right track to have a usable machine or do I need to do anything else? I had heard that lengthening the inlet manifold helps with low revs and torque - does anyone know if this is true? I would like to find a kick start that clears the footpegs -…

Can anyone suggest a reason why it would be a bad idea to chop the down tube on a cub frame and replace with a thick sumpgaurd (as in how the upb and armac design frames are configured). Obviously id have to keep the frame straight while attempting this operation. I would hopefully have a 5mm pre formed alloy bash plate made and replace bottom of downtube with this,can anyone suggest any downfallls pitfalls to this operation.

Hi Guy's. I see that Woody has his C15 for sale on e-Bay. This bike has the power in a C15 that everyone is looking for, I am currently trying to build an engine that is simular. It is a shame, I have now got most of the parts together! Or I would be bidding on Woody's bike. So if you are intrested in a bike that wins trials! I would take a look at this before it is to late? You only have four days. :thumbup: Regards Charlie.

Hi everyone, I've just bought my first AMC bike which is an AJS 16 that's been built as a trials (style) bike. A fair bit has been done to it but there is also a lot I need to sort out and improve upon. The plan is to use it for some road trials like the Arbuthnot, some rides out with my local VMCC sections and a bit of playing around at my trials club's local practice ground. I'm not looking to use it for serious pre-65 competition use. From what I can tell so far, it's quite a bit of a bitsa. I believe the frame is a 1959 but the engine may be earlier as it has a pressed steel primary chaincase and magneto with manual retard control. I was also told that the crankca…